This invention relates to a water seal for a gas line and more particularly to a water valve that provides a simple positive gas shut off in a large diameter gas line.
Blast furnace gas produced in the iron making process is generally distributed in a steel plant through a system of supply lines for use as a fuel in other equipment such as reheating furnaces. The distribution system includes control valves, conventional shut off valves, goggle valves and water seals depending upon the service requirements of the system and safety regulations. Typical installations include arrangements for washing dirt from the gas and disposing of the dirty wash water, such arrangements may also include a positive shut off of the line by providing for a water seal. Some such arrangements that I am aware of require a certain level of water be maintained in some type of sewer trap to be effective as well as safe. Others back up the potentially dirty water against conventional valves which may result in failure to provide a positive shut off and severe maintenance problems. With some other types of water seals there is no adequate method of determining if the seal is effective, and others are subject to failure by plugging from dirt.
In accordance with my invention, a gas supply line is connected to the entrance end of a vertical loop of a gas pipe. A water supply line is connected to supply water for either gas cleaning or sealing into the supply line at the entrance of the loop, and a water drain line is provided at the bottom of the loop. At the exit end of the loop, a horizontal gas discharge line conducts gas away from the loop and a vertical water discharge line conducts water from the loop through a drain seal and a collector to a sewer. The drain line is connected to the water discharge line through a dump valve. Water normally is sprayed into the entrance pipe to clean the gas. The water then passes through the drain line and water discharge line. To establish the seal, the dump valve is closed and water then builds up inside the loop, eventually spilling over the top of the loop, thereby creating the seal. Excess water then passes into the water discharge line.
It is therefore an object of my invention to provide a gas line loop water seal which provides a positive gas shut off,
Another object is to provide a seal in which sealing water does not contact gas line valves.
Still another object is to provide a seal in which the operating parts are not subject to gas flow.